Accounts payable and accrued liabilities - Schedule of Accrued Liabilities (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Accounts payable:
Accounts payable	$ 169.6	$ 196.3
Current accrued liabilities:
Employee benefits*	38.5	45.4
Accrued sales discounts and rebates	14.9	11.8
Environmental costs	7.6	8.6	9.7
Interest	0.3	5.0
Deferred income	5.4	3.5
Reserve for uncertain tax positions	3.0
Other*	42.5	71.7
Total	112.2	146.0
Noncurrent accrued liabilities:
Reserve for uncertain tax positions	29.4	26.9
Asset retirement obligations	23.8	3.9
Insurance claims and expenses	9.7	9.7
Employee benefits	11.3	10.3
Deferred income	1.0	1.1
Other	3.1	3.5
Total	78.3	55.4
Kronos Worldwide, Inc. [Member]
Accounts payable:
Accounts payable	161.3	186.6
CompX [Member]
Accounts payable:
Accounts payable	2.8	6.2
WCS [Member]
Accounts payable:
Accounts payable	0.9	1.1
Other Member [Member]
Accounts payable:
Accounts payable	$ 4.6	$ 2.4